Abstract: Aiming at the obvious problems of high H2S and combustible gas content in the electric desalting wastewater of the atmospheric and vacuum distillation units and the unstable water quality that cannot meet the standard due to the influence of oil and slug content, this paper adopts the combination of atmospheric flash evaporation and high-efficiency cyclone dissolved gas flotation (CDFU) technology routes to match the original gravity sedimentation oil-removal technology process. This effectively solves the problems of high oil content and slag content, combustible gas and hydrogen sulfide in the electric desalination wastewater. After the transformation, the petroleum content is reduced by 73.6%; COD (chemical oxygen demand) is reduced by 32.7% and the volume concentrations of H2S, combustible gas, and VOCs are reduced by 56.85%, 57.93%, and 38.25% respectively. The water quality of the electric desalting wastewater has been improved significantly, which reduces the impact on the downstream wastewater system and eliminates safety hazards.

Key words: electric desalting wastewater, swirling dissolved air flotation, suspended solids, flashing